In general, in a stator for a motor, a winding is wound around a stator core of the stator with an insulator in between, and thus a coil is formed in the stator. It is desirable that the density of the winding (the space factor of the coil) wound around the stator core be large, in order to enhance the performance of the motor. Hence, a stator using a substantially T-shaped stator core has been used; the substantially T-shaped core has corners forming right angles between inner circumferential surfaces of a yoke part and side surfaces of a tooth part. The stator core having the corners forming right angles can increase the density of the winding in the stator. However, in a conventional annular stator core (a stator core that is not composed of split cores), since a winding is inserted between two tooth parts adjacent to each other and winding is performed, it has been difficult to align the winding on the tooth part, regardless of the shapes of the corners. Hence, a split stator composed of a plurality of split cores each including a tooth part is used (e.g., refer to patent reference 1) as a stator for a motor. In this split stator, windings can be wound around the tooth parts in a state in which the split cores are arranged linearly. When the split cores are arranged linearly, since there is a wide space between the adjacent tooth parts, the winding is easily aligned on the tooth part, by winding the winding around the tooth part with a flyer method, for example. Thus, the split stator composed of the split cores including the corners forming right angles makes it easy to align the windings on the tooth parts, and can increase the density of the windings in the split stator.